1. Field of the Invention
The invention relates to braiding machines for filaments and particularly to braiding machines of this type in which two annular arrays of bobbins of filaments of wire, yarn, or the like revolve about a common axis and filament from each of the bobbins is wrapped about this axis, with the filaments from one array being shifted radially inwardly and outwardly of the filaments from the inner array as both bobbin arrays are rotating in opposite directions so as to wind the filament about the axis.
2. Description of the Prior Art
This invention is an improvement upon the braiding apparatus described in my prior U.S. Pat. Nos. 2,464,899 and 3,892,161, both of which earlier patents are incorporated herein by reference.
Both of my earlier patents disclose wire or other filament braiding machines for braiding filaments about a common central axis. Each machine comprises a radially more inward array of bobbins, or reel type filament carriers, or other filament dispensers and the inner array bobbins are rotatable together around the axis in one direction. Each machine also comprises a radially more outward array of similar bobbins, carriers or other filament dispensers rotatable together around the common axis in the opposite direction. As each array rotates, its bobbins supply filament to and wind the filament around a mandrel at the axis.
Respective guide means associated with each outer array bobbin direct the filament therefrom alternately radially inwardly of and outwardly of the annular path of the inner bobbin array as the bobbin arrays rotate. This produces the braid. In both of my prior patents, each guide means comprises a respective guiding tube having an inlet for filament from the respective bobbin and an outlet for the filament. The tube form is not a required feature of the guide means and any other similarly functioning filament supporting structure would suffice. In both of these patents, the tube shifts radially with respect to the axis from a position where the filament exiting from the outlet of the tube would be radially outward of the inner array of bobbins to a position where the filament exiting from the tube outlet would be radially inward of the inner array of bobbins. The respective guide means move annularly around the axis with the radially outward array of bobbins. Means are provided for coordinating this radial shifting of the outlet from the guide means tube with the opposite annular motion of the inward bobbin array to avoid contact between the tubes and the bobbins.
After a filament guiding tube has shifted so that the filament exiting therefrom is radially inward of a bobbin of the inner array, the filament passes inwardly of that inner array bobbin as that inner array bobbin rotates past the tube. Then the guiding tube moves the filament exiting therefrom radially outwardly between the inner array bobbin that has just rotated past the tube and the next inner array bobbin. The filament exiting from the guiding tube passes outwardly of that next inner array bobbin as that inner array bobbin rotates past the filament exit. Next, the guiding tube shifts the filament exiting therefrom radially inwardly between the inner array bobbin it has just passed and the next inner array bobbin. In this manner, each inner array bobbin is eventually passed on all sides by one or another of the filaments exiting from the guiding tubes.
Although the description in the patent is particularly directed to the filaments from each outer array bobbin shifting down between one pair of inner array bobbins and then shifting out between the next adjacent pair of inner array bobbins, by a simple redesign of the camming or other means that controls the guiding tubes, each such filement may pass radially outwardly of two or more of the inner array bobbins before shifting inwardly and then may pass radially inwardly of two or more of the inner array bobbins before shifting radially outwardly.
In both of my prior patents, the filament guide means comprise tubes that shift by pivoting so that the outlets from the guiding tubes move radially inwardly toward the axis of rotation of the array of bobbins and then move radially outwardly away from the axis of rotation of the array of bobbins. When the guide means shifts inwardly, it necessarily somewhat reduces the tension on the filament, even when spring biased compensating or tensioning means are employed for maintaining the tension on the filament at a substantially constant level during the radial shifting of the guide means. When the guide means moves outwardly, on the other hand, it necessarily increases the tension on the filament, again despite any idler or tensioning means. Because precisely uniform tension cannot be maintained, there is a slight adverse effect upon the uniformity of the quality of the resultant braid of filament that is produced. A braider which uses a compensator or web tensioning means may be adequate when a cheaper type of braid is being wound, for example, inexpensive threads or wires. However, where precise braiding is required, as with high tension wire, variations in the tension of the filament, despite the presence of a compensating or tensioning means, is highly undesirable.
In other known braiding machines, shifting of the filaments of the outer array bobbins radially inwardly and outwardly of the inner array bobbins is accomplished by filament engaging deflection cams or deflectors positioned so as to be periodically engaged by each radially outer bobbin array filament as the braid is being wound. In one known arrangement, the filament deflectors are generally fixedly positioned and supported on the frame of the braiding machine so that the outer array filaments engage the deflectors as they move by. Each outer array filament is fed through a feeding element positioned so as to normally feed the filament radially inwardly of the inner array bobbins, and the deflectors are so shaped and placed as to lift each filament as it engages each deflector to raise the outer array filament so as to be radially outside of the inner array bobbin then passing by.
In another aspect of these apparatus, the deflectors are one-way bobbin motion deflectors in that they are shaped to raise the filament radially outwardly as the outer array bobbins are moving in a main winding direction. However, should the rotation direction of the outer bobbin array be reversed, for example, in the event that it is necessary to partially unwind the braid for any reason or if it is desired to wind the braid in the opposite direction, the deflectors are not shaped to desirably deflect the filaments radially outwardly past the inner array bobbins but instead the deflectors will simply snag the filaments and tear them.
As an outer bobbin array filament disengages from a deflector so as to move radially inwardly between two inner array bobbins, it should be free of any contact with the deflector. During movement of the outer bobbin array in the reverse direction, the known deflector will not be present to lift the outer array filament from between the two inner array bobbins because that deflector had been positioned to be out of the outer array filaments moving in the main winding direction and moving between the inner array bobbins. It would be helpful, therefore, for a deflector to be repositionable so that it would properly deflect the outer array filament regardless of which direction the filament array bobbins rotate.